Functional characterization of OX40 expressed on human CD8+ T cells

Immunol Lett. 2006 Jul 15;106(1):27-33. doi: 10.1016/j.imlet.2006.04.001. Epub 2006 Apr 25.


In the present study, we investigated the expression of OX40 on human CD8(+) T cells with regard to expression induction, costimulatory function and possible involvement in cytotoxicity. Human CD8(+) T cells were purified from peripheral blood mononuclear cell (PBMC) of healthy donors and cocultured with allogeneic monocyte-derived dendritic cells. Flow cytometric analysis showed that expression of OX40 was induced on CD8(+) T cells within 1 day and increased to the maximum levels on day 3. An addition of anti-OX40 ligand (OX40L) mAb suppressed CD25 expression, proliferation and IFN-gamma production of CD8(+) T cells, suggesting that OX40 functions as a costimulatory molecule not only for CD4(+) T cells but also for CD8(+) T cells. In parallel, coculture of pre-activated CD8(+) T cells with OX40L-transfected murine epithelial cells (MMCE-OX40L) resulted in an increase in CD25 expression, proliferation and IFN-gamma producing cells, compared with that with the mock control (MMCE-mock). Finally, non-specific cytotoxic activity of preactivated CD8(+) T cells was examined using OKT3 hybridoma as target cells after coculture with these transfectants. Coculture with MMCE-OX40L induced slightly higher cytotoxicity of CD8(+) T cells than that with MMCE-mock. These results indicate that OX40 is induced transiently on CD8(+) T cells upon activation and its signals contribute to both clonal expansion and functional reinforcement.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal / immunology
  • CD8-Positive T-Lymphocytes / cytology
  • CD8-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / metabolism*
  • Cell Proliferation
  • Cells, Cultured
  • Coculture Techniques
  • Dendritic Cells / immunology
  • Humans
  • Interferon-gamma / metabolism
  • Lymphocyte Activation / immunology
  • Receptors, Interleukin-2 / metabolism
  • Receptors, OX40
  • Receptors, Tumor Necrosis Factor / immunology
  • Receptors, Tumor Necrosis Factor / metabolism*
  • Signal Transduction
  • Transfection


  • Antibodies, Monoclonal
  • Receptors, Interleukin-2
  • Receptors, OX40
  • Receptors, Tumor Necrosis Factor
  • TNFRSF4 protein, human
  • Interferon-gamma